Carbon nanotubes are nanoscale high-aspect-ratio cylinders consisting of hexagonal rings of carbon atoms that may assume semi-conducting and conducting electronic states. Carbon nanotubes typically range from a few to tens of nanometers in diameter and tens to hundreds of nanometers in length. Because of their unique structure, carbon nanotubes have a conductivity far greater than of a typical copper interconnect. Further, with respect to heat conduction, the carbon nanotube has a conductivity about ten times higher than copper.
Many methods exist for forming and/or creating nanotubes. A conventional method of forming carbon nanotubes utilizes a chemical vapor deposition (CVD) process. Specifically, the CVD process directs a flow of a carbonaceous reactant to a catalyst material located on the substrate, where the reactant is catalyzed to synthesize carbon nanotubes. Commonly used carbonaceous materials used for the construction of carbon nanotubes include materials such as activated carbon, carbon black, carbon fiber cloth, highly oriented pyrolytic graphite, graphite powder, graphite cloth, glassy carbon, carbon aerogel, and the like. The carbon nanotubes are capable of being lengthened by insertion of activated carbon atoms at the interface with the catalyst material. Typically, the carbon nanotubes are then collected for an end use or further processing.
In designing components for electronic, optical, and other applications, for example, it is desirable to control the lengths, diameters, and types of carbon nanotubes produced. Additionally, it would be beneficial to build on the paucity of methods available to control the overall three dimensional architecture of carbon nanotube arrays.